>
> Doesn't appear to be related to kvm. Copying lkml.
>
> >When doing:
> >
> >echo noop>/sys/block/vdd/queue/scheduler
> >
> >I got:
> >
> >[ 1424.438241] =============================================
> >[ 1424.439588] [ INFO: possible recursive locking detected ]
> >[ 1424.440368] 2.6.33.3-moocow.20100429-142641 #2
> >[ 1424.440960] ---------------------------------------------
> >[ 1424.440960] bash/2186 is trying to acquire lock:
> >[ 1424.440960] (s_active){++++.+}, at: [<ffffffff811046b8>] sysfs_remove_dir+0x75/0x88
> >[ 1424.440960]
> >[ 1424.440960] but task is already holding lock:
> >[ 1424.440960] (s_active){++++.+}, at: [<ffffffff81104849>] sysfs_get_active_two+0x1f/0x46
> >[ 1424.440960]
> >[ 1424.440960] other info that might help us debug this:
> >[ 1424.440960] 4 locks held by bash/2186:
> >[ 1424.440960] #0: (&buffer->mutex){+.+.+.}, at: [<ffffffff8110317f>] sysfs_write_file+0x39/0x126
> >[ 1424.440960] #1: (s_active){++++.+}, at: [<ffffffff81104849>] sysfs_get_active_two+0x1f/0x46
> >[ 1424.440960] #2: (s_active){++++.+}, at: [<ffffffff81104856>] sysfs_get_active_two+0x2c/0x46
> >[ 1424.440960] #3: (&q->sysfs_lock){+.+.+.}, at: [<ffffffff8119c3f0>] queue_attr_store+0x44/0x85
> >[ 1424.440960]
> >[ 1424.440960] stack backtrace:
> >[ 1424.440960] Pid: 2186, comm: bash Not tainted 2.6.33.3-moocow.20100429-142641 #2
> >[ 1424.440960] Call Trace:
> >[ 1424.440960] [<ffffffff8105e775>] __lock_acquire+0xf9f/0x178e
> >[ 1424.440960] [<ffffffff8100d3ec>] ? save_stack_trace+0x2a/0x48
> >[ 1424.440960] [<ffffffff8105b46c>] ? lockdep_init_map+0x9f/0x52f
> >[ 1424.440960] [<ffffffff8105b46c>] ? lockdep_init_map+0x9f/0x52f
> >[ 1424.440960] [<ffffffff8105cb56>] ? trace_hardirqs_on+0xd/0xf
> >[ 1424.440960] [<ffffffff8105f02e>] lock_acquire+0xca/0xef
> >[ 1424.440960] [<ffffffff811046b8>] ? sysfs_remove_dir+0x75/0x88
> >[ 1424.440960] [<ffffffff8110458d>] sysfs_addrm_finish+0xc8/0x13a
> >[ 1424.440960] [<ffffffff811046b8>] ? sysfs_remove_dir+0x75/0x88
> >[ 1424.440960] [<ffffffff8105cb25>] ? trace_hardirqs_on_caller+0x110/0x134
> >[ 1424.440960] [<ffffffff811046b8>] sysfs_remove_dir+0x75/0x88
> >[ 1424.440960] [<ffffffff811ab312>] kobject_del+0x16/0x37
> >[ 1424.440960] [<ffffffff81195489>] elv_iosched_store+0x10a/0x214
> >[ 1424.440960] [<ffffffff8119c416>] queue_attr_store+0x6a/0x85
> >[ 1424.440960] [<ffffffff81103237>] sysfs_write_file+0xf1/0x126
> >[ 1424.440960] [<ffffffff810b747f>] vfs_write+0xae/0x14a
> >[ 1424.440960] [<ffffffff810b75df>] sys_write+0x47/0x6e
> >[ 1424.440960] [<ffffffff81002202>] system_call_fastpath+0x16/0x1b
> >
> >Original scheduler was cfq.
> >
> >Having rebooted and defaulted to noop I tried
> >
> >echo noop>/sys/block/vdd/queue/scheduler
> >
> >and got:
> >
> >[ 311.294464] =============================================
> >[ 311.295820] [ INFO: possible recursive locking detected ]
> >[ 311.296603] 2.6.33.3-moocow.20100429-142641 #2
> >[ 311.296833] ---------------------------------------------
> >[ 311.296833] bash/2190 is trying to acquire lock:
> >[ 311.296833] (s_active){++++.+}, at: [<ffffffff81104630>] remove_dir+0x31/0x39
> >[ 311.296833]
> >[ 311.296833] but task is already holding lock:
> >[ 311.296833] (s_active){++++.+}, at: [<ffffffff81104849>] sysfs_get_active_two+0x1f/0x46
> >[ 311.296833]
> >[ 311.296833] other info that might help us debug this:
> >[ 311.296833] 4 locks held by bash/2190:
> >[ 311.296833] #0: (&buffer->mutex){+.+.+.}, at: [<ffffffff8110317f>] sysfs_write_file+0x39/0x126
> >[ 311.296833] #1: (s_active){++++.+}, at: [<ffffffff81104849>] sysfs_get_active_two+0x1f/0x46
> >[ 311.296833] #2: (s_active){++++.+}, at: [<ffffffff81104856>] sysfs_get_active_two+0x2c/0x46
> >[ 311.296833] #3: (&q->sysfs_lock){+.+.+.}, at: [<ffffffff8119c3f0>] queue_attr_store+0x44/0x85
> >[ 311.296833]
> >[ 311.296833] stack backtrace:
> >[ 311.296833] Pid: 2190, comm: bash Not tainted 2.6.33.3-moocow.20100429-142641 #2
> >[ 311.296833] Call Trace:
> >[ 311.296833] [<ffffffff8105e775>] __lock_acquire+0xf9f/0x178e
> >[ 311.296833] [<ffffffff8105b46c>] ? lockdep_init_map+0x9f/0x52f
> >[ 311.296833] [<ffffffff8105b46c>] ? lockdep_init_map+0x9f/0x52f
> >[ 311.296833] [<ffffffff8105cb56>] ? trace_hardirqs_on+0xd/0xf
> >[ 311.296833] [<ffffffff8105f02e>] lock_acquire+0xca/0xef
> >[ 311.296833] [<ffffffff81104630>] ? remove_dir+0x31/0x39
> >[ 311.296833] [<ffffffff8110458d>] sysfs_addrm_finish+0xc8/0x13a
> >[ 311.296833] [<ffffffff81104630>] ? remove_dir+0x31/0x39
> >[ 311.296833] [<ffffffff8105cb25>] ? trace_hardirqs_on_caller+0x110/0x134
> >[ 311.296833] [<ffffffff81104630>] remove_dir+0x31/0x39
> >[ 311.296833] [<ffffffff811046c0>] sysfs_remove_dir+0x7d/0x88
> >[ 311.296833] [<ffffffff811ab312>] kobject_del+0x16/0x37
> >[ 311.296833] [<ffffffff81195489>] elv_iosched_store+0x10a/0x214
> >[ 311.296833] [<ffffffff8119c416>] queue_attr_store+0x6a/0x85
> >[ 311.296833] [<ffffffff81103237>] sysfs_write_file+0xf1/0x126
> >[ 311.296833] [<ffffffff810b747f>] vfs_write+0xae/0x14a
> >[ 311.296833] [<ffffffff810b75df>] sys_write+0x47/0x6e
> >[ 311.296833] [<ffffffff81002202>] system_call_fastpath+0x16/0x1b
> >
> >Changing back to noop (or, in the initial case to cfq) did not
> >reproduce the message.
> >
> >This does not happen when the elevator is explicitly set on bootup as
> >part of the kernel's commandline. Compiled-in default is cfq.
> >
>
>
> --
> error compiling committee.c: too many arguments to function
>
> --
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